Question: $-\dfrac{7}{4} + \dfrac{5}{12} = {?}$
Answer: $ = - {\dfrac{7 \times 3}{4 \times 3}} + {\dfrac{5 \times 1}{12 \times 1}} $ $ = - {\dfrac{21}{12}} + {\dfrac{5}{12}} $ $ = - \dfrac{{21} + {5}}{12} $ $ = -\dfrac{16}{12}$